1. Field of the Invention
This invention relates to a process for the synthesis of the porous crystalline material MCM-58, to MCM-58 produced by said process, and to use of the resultant MCM-58 as a catalyst for organic compound, e.g. hydrocarbon compound, conversion.
2. Discussion of the Prior Art
MCM-58 and its conventional preparation in the presence of N-benzylquinuclidinium cations as the directing agent are taught by U.S. Pat. No. 5,437,855, the entire disclosure of which is incorporated herein by reference. MCM-58 has a distinctive X-ray diffraction pattern which distinguishes it from other known crystalline materials.
U.S. Pat. No. 5,441,721 discloses a method for the synthesis of MCM-58 from a reaction mixture comprising, as a directing agent, the novel cation, N-benzyltropanium cation which can be synthesized by reacting benzyl bromide with tropane.
U.S. Pat. No. 5,653,956 discloses a method for the synthesis of SSZ-42, which is isostructural with MCM-58, using an organic templating agent selected from the group consisting of N-benzyl-1,4-diazabicyclo[2.2.2]octane cations and N-benzyl-1-azabicyclo[2.2.2]octane cations. ITQ-4 is also isostructural with MCM-58 and, according to PCT Publication No. 98/29332, can be synthesized using N-benzylquinuclidinium cations or N-benzyl-1,4-diazabicyclo[2.2.2]octane cations as the directing agent.
The existing methods for the synthesis of MCM-58 and the related materials SSZ-42 and ITQ-4 suffer from the problem that they require the use of expensive materials as the directing agent. According to the present invention, it has now been found that MCM-58 can be synthesized using, as directing agent, 1-(1-adamantyl)pyridinium cations, which can be produced from, for example, the relatively inexpensive starting materials adamantyl bromide and pyridine.
It is to be appreciated that, although MCM-58 is normally synthesized as an aluminosilicate, the framework aluminum can be partially or completely replaced by other trivalent elements, such as boron, iron and/or gallium, and the framework silicon can be partially or completely replaced by other tetravalent elements such as germanium.
According to the invention, there is provided a process for synthesizing the porous, crystalline material MCM-58 which comprises the steps of:
(i) preparing a mixture capable of forming said material, said mixture comprising sources of alkali or alkaline earth metal (M), an oxide of trivalent element (X), an oxide of tetravalent element (Y), hydroxyl (OHxe2x88x92) ions, water and a 1-(1-adamantyl)pyridinium directing agent (R), wherein said mixture has a composition, in terms of mole ratios, within the following ranges:
YO2/X2O3=10-1000
H2O/YO2=5-100
OHxe2x88x92/YO2=0.005-1
M/YO2=0.05-1
R/YO2=0.01-0.4
(ii) maintaining said mixture under sufficient conditions until crystals of said material are formed; and (iii) recovering said crystalline material from step (ii).
Preferably, said reaction mixture has a composition in terms of mole ratios within the following ranges:
YO2/X2O3=20-100
H2O/YO2=10-50
OHxe2x88x92/YO2=0.1-0.4
M/YO2=0.1-0.4
R/YO2=0.05-0.2